If you’re like most people, you’re pretty sure you know aggression when you see it. So here’s a pop quiz: Is it “aggression” when your 8-week-old puppy nips you? How about your adult dog chasing a rabbit he spots on an off-leash hike – is he being “aggressive”? Or what if Dogalini has a bone, Zippy approaches, and Dogalini curls her lip at him. Is Dogalini being “aggressive”? Bonus question: Is “aggression” a bad thing?

It’s upsetting when our dogs bark, snarl, and lunge at other dogs, or when they growl at us if we approach them while they’re eating. Many people don’t mind if their Zippy chases a squirrel, but heaven forbid he should catch that squirrel and kill it. (And never mind that most of us eat animals too.) When you combine emotional distress with the wealth of misinformation available on the Internet, it’s no wonder we find it so hard to think clearly about certain kinds of dog behavior. And what we have trouble thinking clearly about, we also have trouble handling successfully. So I’ll try to unpack “aggression” for you.

One reason humans get so upset about aggression is that we equate it with violence. It might help to think about aggression in the larger context of what scientists call “agonistic” behaviors. These are behaviors related to social conflict. Among dogs, agonistic behaviors include not just barking, growling, biting, and the other behaviors we think of as aggressive, but also appeasing behaviors such as lifting a forepaw and rolling on the back to expose the groin and belly. In human terms, agonistic behaviors might range from smiling apologetically, to using lots of “I” statements when arguing with your spouse, to filing a lawsuit, to starting a war. And in both species, the most important thing about agonistic behaviors is that very few involve bloodshed.

Scientific American is part of Springer Nature, which owns or has commercial relations with thousands of scientific publications (many of them can be found at www.springernature.com/us). Scientific American maintains a strict policy of editorial independence in reporting developments in science to our readers.